Thread: question on radon findings

Hello all, I hope someone can help. I am in the process of selling my home on Cape Cod. A radon test was done in the unfinished basement and came back as 4.3 and 4.1 and it should be below 4.0. I was told to have another reading done and also told I need to remedy this which can be done not to expensively. I am not familiar with radon nor do I know anyone in the cape cod area. Can someone shed some light on this for me and what needs to be done and possibly who can do it.. I have talked to other friends on the cape and they told me their radon test came back in the 8's and 9. Any information anyone can give would be appreciated.

Thanks for your time.

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Scott,
The EPA link should point you in the right direction: Who Can Test or Fix Your Home? | Radon | Indoor Air Quality | Air | US EPA

In my area, a mitigation system is around $1000. Could be more depending upon square footage, if there are earth sections within the basement (crawlspaces), and several other factors.

Originally Posted by scott glincher

Hello all, I hope someone can help. I am in the process of selling my home on Cape Cod. A radon test was done in the unfinished basement and came back as 4.3 and 4.1 and it should be below 4.0. I was told to have another reading done and also told I need to remedy this which can be done not to expensively. I am not familiar with radon nor do I know anyone in the cape cod area. Can someone shed some light on this for me and what needs to be done and possibly who can do it.. I have talked to other friends on the cape and they told me their radon test came back in the 8's and 9. Any information anyone can give would be appreciated.

Thanks for your time.

It sounds like two canister type test were used. They are fairly accurate but have some variance and that is why you use two of the side by side. You could have another test done to confirm the results of the first test, and I would recommend using a company that has electronic constant radon measurement machines (CRM's). A CRM tends to be a little more accurate and the results are available after 48 hours or when the test is done, unlike the canisters that have to be sent to a lab.

If the readings come back over 4.0 pCi/L then you need to have a mitigation system installed in the home.

Have your problem fixed and them retest. If you are in a real Estate transaction most buyers will be skeptical of your retest...
MA Info
Radon Levels for Massachusetts

National Radon Safety Board
Specialist Locator

National Environmental Health Association -NRPP
National Environmental Health Association National Radon Proficiency Program - Mitigation Professionals

Your home is borderline and I recommend that you do another radon test, either another short-term test or, preferrably, a long-term test.

If you followed the EPA protocols for short-term (ST) testing what you actually measured is your home's potential for a radon problem. Short-term test protocols require (among other things) all exterior doors and windows to be closed for at least 12 hours before and during the test period. Under these conditions radon is allowed to build up to a concentration that is most likely higher than if the doors and windows had been open. So the short-term test provides an indication of the home's potential for radon but not necessarily the radon concentration under normal lived-in conditions. Due to time constraints, most radon tests for real estate transactions are short-term tests.

Radon levels in a home are constantly changing. Weather plays a large part in how much radon a home draws in from the soil. You can do 2 or more radon tests in a home in the exact same location but during different time periods and get drastically different results. A ST test only tells you what the radon level was under the conditions that existed during the time period of the test - a snapshot so to speak.

EPA protocols for long-term (LT) testing do not require the doors and windows to be closed so, unlike a ST test which measures a home's potential for radon, a LT test measures the actual radon levels the occupants are exposed to under real-life conditions. A LT test averages out all the highs and lows and gives you an accurate measurement of the home's average radon concentration during the measurement period. (A good analogy is calculating your car's gas mileage. You get a much more accurate measurement by calculating the mileage over several tanks of gas rather than on one tank of gas.) A long-term test takes a minimum of 91 days to complete and can last up to one year.

If you have at least 91 days I would recommend that you consider doing a long-term radon test. There are several different devices, the most common being the Alpha Track Detector (ATD - which takes some time to be processed at a lab) and an E-PERM (which can be processed immediately by a radon professional).

Assuming you followed EPA protocol when you did your radon test your measured radon concentration is 4.2 pCi/L (which is the average of the two canisters). The two measurements were very close so I would feel comfortable with those results.

Understand that 4.2 pCi/L is only slightly above the EPA action level of 4.0 pCi/L. I would not automatically recommend mitigation based on this one test. Instead I would recommend (per EPA's recommendations) that you consider doing more testing - either another ST test or, preferrably, a LT test. That said, there is no safe level of radon so even mitigating a home that measures below the 4.0 pCi/L action level will provide some benefit to the occupants.

A word about charcoal canisters: Charcoal canisters are an approved EPA radon device but they have a relatively large margin of error at the radon levels you measured. The figures I have seen quoted are +/- 25%. That means your actual radon concentration (during the test period) could be as low as 3.2 or as high as 5.3 pCi/L.

Other devices have better accuracy. E-PERMS are about +/- 5%. I don't know the accuracy of Continuous Radon Monitors (CRMs) but it is considerably less than +/- 25%. You will need to hire a radon measurement professional to have a radon test done with these devices.

Please consult your state radon office or a radon measurement professional in your area for advice. If you use a radon measurement or mitigation professional I would recommend that you ensure he (or she) is certified by either NEHA (National Environmental Health Association) or NRSB (National Radon Safety Board).

As Bruce points out two test are better yet EPA protocol during real estate transactions require a single test (2 passive devices at the same time) or two sequential tests (passive devices) one right after the other. Both testing protocols are averaged and given as the final result. If using an active device a single device is only required. These are all short term testing.

If doing a test as a home owner (Not Real Estate transaction) two separate tests should be done and then if both tests are 4 pCi/L or greater mitigation is recommended. Of course Long term testing is prefered.


Copied from EPA Home buyers and sellers guide.
EPA 402-K-06-093, November 2006

If you are testing in a real estate transaction and you need results quickly, any of the following three options for short-term Tests are acceptable in determining whether the home should be fixed. Any real estate test for radon should include steps to prevent or detect device interference with the test device.

Short-Term Testing Options What to do Next
Passive:
Take two short-term tests at the same time in the same location for at least 48 hours.

Fix the home if the average of two tests is 4 pCi/L or more.

or

Take an initial short-term test for at least 48 hours. Immediately upon completing the first test, do a second test using an identical device in the same location as the first test.

Fix the home if the average of the two tests is 4 pCi/L or more.

Active:
Test the home with a continuous monitor for at least 48 hours.

Fix the home if the average radon level is 4 pCi/L or more.

The EPA's website at:

http://www.epa.gov/radon/healthrisks.html , states:

• "The average radon concentration in the indoor air of America's homes is about 1.3 pCi/L. It is upon this level that EPA based its estimate of 20,000 radon-related lung cancers a year upon. It is for this simple reason that EPA recommends that Americans consider fixing their homes when the radon level is between 2 pCi/L and 4 pCi/L. "
  
• "Unfortunately, many Americans presume that because the action level is 4 pCi/L, a radon level of less than 4 pCi/L is "safe". This perception is altogether too common in the residential real estate market. In managing any risk, we should be concerned with the greatest risk. For most Americans, their greatest exposure to radon is in their homes; especially in rooms that are below grade (e.g., basements), rooms that are in contact with the ground and those rooms immediately above them."

The EPA's "

Home Buyer's & Seller's Guide to Radon" states

• "Radon levels less than 4 pCi/L still pose a risk and, in many cases, may be reduced."
  
• "Short-term tests can be used to decide whether to reduce the home's high radon levels. However, the closer the short-term testing result is to 4 pCi/L, the less certainty there is about whether the home's year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk and that radon levels can be reduced to 2 pCi/L or below in most homes."